drm/msm/dpu: decide right side per last bit

Currently, only one pair of mixers is supported, so a non-zero counter
value is sufficient to identify the correct mixer within that pair.
However, future implementations may involve multiple mixer pairs. With
the current implementation, all mixers within the second pair would be
incorrectly selected as right mixer. To correctly select the mixer
within a pair, test the least significant bit of the counter. If the
least significant bit is not set, select the mixer as left one;
otherwise, select the mixer as right one for all pairs.

Signed-off-by: Jun Nie <jun.nie@linaro.org>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Reviewed-by: Jessica Zhang <quic_jesszhan@quicinc.com>
Patchwork: https://patchwork.freedesktop.org/patch/669226/
Link: https://lore.kernel.org/r/20250819-v6-16-rc2-quad-pipe-upstream-v15-3-2c7a85089db8@linaro.org
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>

diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c
index d59512e45af0531ab6bb59a2c8fdf42129ebef40..4b970a59deafdae3eb964da912e7f1f1d181eec7 100644 (file)
--- a/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c
+++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c
@@ -377,11 +377,10 @@ static void _dpu_crtc_setup_blend_cfg(struct dpu_crtc_mixer *mixer,
 static void _dpu_crtc_program_lm_output_roi(struct drm_crtc *crtc)
 {
        struct dpu_crtc_state *crtc_state;
-       int lm_idx, lm_horiz_position;
+       int lm_idx;
 
        crtc_state = to_dpu_crtc_state(crtc->state);
 
-       lm_horiz_position = 0;
        for (lm_idx = 0; lm_idx < crtc_state->num_mixers; lm_idx++) {
                const struct drm_rect *lm_roi = &crtc_state->lm_bounds[lm_idx];
                struct dpu_hw_mixer *hw_lm = crtc_state->mixers[lm_idx].hw_lm;
@@ -392,7 +391,7 @@ static void _dpu_crtc_program_lm_output_roi(struct drm_crtc *crtc)
 
                cfg.out_width = drm_rect_width(lm_roi);
                cfg.out_height = drm_rect_height(lm_roi);
-               cfg.right_mixer = lm_horiz_position++;
+               cfg.right_mixer = lm_idx & 0x1;
                cfg.flags = 0;
                hw_lm->ops.setup_mixer_out(hw_lm, &cfg);
        }